This invention relates to a punctum plug for removably closing the punctal openings of the eye and a method for treating keratoconjunctivitis sicca and other ophthalmic ailments using the plug as a means for preventing drainage of the lacrimal fluid from the eye or as a carrier vehicle for storing and delivering medication to the eye.
Keratitis sicca or keratoconjunctivitis sicca (referred to in layman's terms as dry eye), due to insufficient production or excessive drainage of lacrimal fluid, is a frequently-encountered ophthalmic problem, especially in elderly patients. Conventional prior art practice in treating such condition has been to utilize various types of topical drops and ointments with varying degrees of success. Humidifiers or vaporizers have also been used and are often of great help in decreasing evaporation from the dry eye, but do nothing to limit the drainage of the lacrimal fluid. In extreme cases of discomfort and pain, such as occurs in Sjogren's syndrome, permanent closure of the punctae and canaliculae by surgery or cauterization has produced marked success. However, each of the aforementioned treatments possess certain inherent limitations, the ointments by reason of the need for frequent and continued applications, and the surgical or cauterization procedure by reason of cost, danger of infection and irreversibility.
A paper by Lester T. Jones et al entitled "Lacrimal Function," appearing in American Journal of Ophthalmology, vol. 73, May 1972, pp. 658-659, described some brief experiments on student nurses using a tapered awl-like cone or tube of polyethylene material to temporarily occlude, for very short periods of time, either the upper or lower punctum and canaliculus while measurements were taken of the relative speed of lacrimal excretion through the unblocked other canaliculus. However, no effort has hithertofore been directed to utilizing a removable punctum plug as a means for treating keratoconjunctivitis sicca or other ophthalmic ailments or to designing a plug of suitable configuration for ready insertion, snug fitting without danger of ejection from the punctum or passage down into the canaliculus, and ready removal from the punctal opening. Nor has consideration been given to forming such a punctum plug from materials which would be readily sterilizable and non-irritating to the ophthalmic tissue structure over long-term wearing periods, and possessing sufficient tensile strength to resist breakage. Finally there has been no discussion in the prior art of utilizing a punctum plug as a vehicle or carrier means for storing and delivering topical medications to the eye over sustained periods of time.